<html>
<body>
  <canvas width="500" height="500"></canvas>
<script>
  var canvas = document.getElementsByTagName('canvas')[0];
  var ctx = canvas.getContext('2d');
  ctx.scale(0.5, 0.5);

  ctx.translate(41, 41.);
  ctx.rect(0, 0, 100, 100);
  ctx.translate(100, 0);
  ctx.moveTo(0,0);
  ctx.quadraticCurveTo(100, 100, 200,0);
  ctx.translate(200, 0);
  ctx.moveTo(0,0);
  ctx.bezierCurveTo(100, 100, 200, -100, 300,0);

  ctx.stroke();
</script>
</body>
</html>
